Cryogenic pumps are commonly used to pressurize a cryogenic liquid for use. For example, a cryogenic pump may be used to pressurize a cryogenic liquid, such as liquid natural gas (LNG), to be vaporized and used as fuel in an internal combustion engine. A vaporizer transfers heat to the fuel, converting the fuel from liquid state to gaseous state before supplying it to the engine. The cryogenic pump typically includes plungers or pistons to pressurize the liquid fuel. These plungers or pistons may be actuated or driven by mechanical or hydraulic actuators either directly or through additional components, such as push rods. Cryogenic pumps typically employ one or more seals to inhibit leakage of the cryogenic liquid past the plunger or piston. However, these seals are susceptible to damage from debris, which may eventually cause a leakage of the cryogenic liquid outside the pumping chamber, thereby reducing the efficiency of the pump, which is undesirable.
US Patent Publication no. 2008/0213110 (hereinafter referred to as the '110 publication) relates to an apparatus and method for pressurizing a cryogenic media. The '110 publication describes a compressor including a compressor chamber surrounded by a cylinder wall in which a compressor piston is moved in a linear manner, a suction valve and a pressure valve, which are arranged in the region of the lower end position of the compressor piston, and a liquid chamber which at least partially surrounds the compressor chamber. The cylinder wall defines at least one opening, which corresponds to the liquid chamber, and at least one opening, via which the gaseous medium can be extracted from the compressor chamber, where the openings are located at points on the cylinder wall that are passed by the compressor piston.